Ooo I really liked this one. I'm generally fond of the stories where Teddy is Lily's professor, but this one didn't take it too far. I'm also glad you left the ending where you did; sometimes one doesn't need to know more. (I can't believe I just said that).

/"Lily, we can't do this," he insists, not letting go of her. "You're too young, I'm too old – and I'm your teacher, for Merlin's sake."

"Say that with feeling," she retorts, and he can't and she's found magic so she's not letting this go, not ever.

"Godric, Lily," he groans, and he's bending to kiss her again and Lily arches up into him and feels the magic of the moment just falling, falling right into place.

There, in the warm cage of his arms with his lips on hers and all the challenges falling away until there's just her and him and the heat of the fire on their skin – there Lily Luna Potter starts to believe in magic./

I really do think this is one of your best pieces. And I really can't picture Lily as anything other than a Slytherin, you know? It's just so /Lily/ and all that. :)